At the beginning of the large screen digital televisions, the amount of power used by them was about on the same level with household irons. Plasma televisions at one time used between 900 and a kilowatt of power depending on the screen size. The introduction of LCD large screen televisions substantially cut that power requirement. Typical large screen LCD televisions then used on the order of 100 watts of power when operating and somewhat less than 2 or 3 watts in standby mode.
Standby power consumption has dropped substantially over the past 10 years. Digital televisions previously turned off power to the display screen when the user would “turn off” the device. In a continual quest to save power, televisions often now turn off power to complete subassemblies.
Televisions generally contain multiple microprocessors for managing digital content. Many times a single chip will contain multiple processing cores much like the multi core processing chips in desktop, laptop and tablet computers.
Televisions with multi-core processing chips will generally put some or all of the processors to sleep or into what is known as deep sleep or hibernation mode. When the processors are put to sleep, the processor clock is generally reduced in frequency or completely stopped. Also, power is generally removed from dynamic random access memory. Once the memory and processors loose power, the operating system that controls the processors is lost. When the user “turns on” the television, power is restored to the memory and to the processor(s). When this happens the processor has to be rebooted which includes moving the operating system(s) from flash memory to faster dynamic memory. The process of rebooting can take anywhere from tens of seconds to over a minute. Times of tens of seconds has the appearance to users of being an inordinate amount of time.